This study examines the pharmacokinetic profile of Armstrong's proposed Epinephrine Inhalation Aerosol USP, an HFA134a propelled Metered Dose Inhaler (MDI) (E004), using a stable isotope deuterium-labeled epinephrine (epinephrine-d3) to differentiate the administered drug from the endogenous epinephrine, in healthy male and female adult volunteers.